ATSAMD21J16B-AF - 48MHz Cortex-M0+ MCU, 64KB Flash | Microchip
MPN: ATSAMD21J16B-AF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.36 | $336.00 |
| 500 | $2.95 | $1,475.00 |
| 1,000 | $2.52 | $2,520.00 |
ATSAMD21J16B-AF Overview
A microcontroller (MCU) is an integrated circuit that combines a CPU core, memory, and programmable peripherals into a single chip. Within the embedded systems hierarchy, an MCU sits between a microprocessor (which requires external memory) and a system-on-chip (which integrates higher-level application processors). The Cortex-M0+ core places this MCU in the entry-level 32-bit tier, optimized for deterministic interrupt response, low active current, and aggressive sleep modes for battery-powered designs.
Key features of the ATSAMD21J16B-AF include a single-cycle hardware multiplier, a Micro Trace Buffer for lightweight instruction trace, six Serial Communication Interfaces (SERCOM) configurable as UART/SPI/I2C, a 12-channel DMA controller and 12-channel Event System for peripheral-to-peripheral signaling, plus full-speed USB 2.0 device/host support. Advanced peripherals include a 12-bit 350 ksps ADC with up to 20 channels, a 10-bit 350 ksps DAC, two analog comparators, and a 24-bit Timer/Counter for Control (TCC). The device also supports capacitive touch via the Peripheral Touch Controller (PTC).
The SAM D21 architecture integrates a 48 MHz Digital Frequency Locked Loop (DFLL48M) and a 48 MHz to 96 MHz Fractional Digital Phase-Locked Loop (FDPLL96M) on-chip, eliminating the need for an external crystal in many designs. A two-pin Serial Wire Debug (SWD) interface handles programming and test, and the part is drop-in compatible with the SAM D20 family for easy migration.
Typical applications include IoT sensor nodes, consumer wearables, industrial HMI panels, USB human-interface devices, capacitive-touch user interfaces, and low-power wireless sensor hubs. Its combination of 64KB Flash and SERCOM flexibility makes it well-suited to protocols like BLE co-processor interfaces, LoRa command shells, and CAN bus nodes through external transceivers.
When designing with this device, provide a 1uF and 0.1uF decoupling pair close to VDDCORE and VDDIO, follow the recommended 32.768 kHz crystal layout for RTC accuracy, and ensure the SWD reset circuit allows both programming and application reset. AEC-Q100 qualification (where applicable via the -AF variant) makes the part attractive for automotive body and chassis ECUs.
This page synthesizes distributor pricing, drop-in alternatives drawn from the same SAM D21 family, and practical design notes that complement the manufacturer datasheet.
Drop-in alternatives for ATSAMD21J16B-AF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATSAMD21J16B-AF (same form factor and footprint) — differing in ADC, Package, Operating Temperature, MSL Level, USB.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J16B-AFT
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →ATSAMD21J15B-AUT
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.4 / Unit
View Datasheet →ATSAMD21G18A-AF
✅ Drop-In✓ In Stock
$3.49 / Unit
View Datasheet →ATSAMD21G17A-AF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.15 / Unit
View Datasheet →ATSAMD21E16B-AF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.19 / Unit
View Datasheet →ATSAMD21G15B-AF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.78 / Unit
View Datasheet →ATSAMD21J16B-AF Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Maximum CPU Frequency | 48 MHz |
| CoreMark/MHz | 2.46 |
| Flash Memory | 64 KB |
| SRAM | 8 KB |
| Supply Voltage (VDDIO) | 1.62 V to 3.63 V (3.3 V typical) |
| Operating Temperature | -40C to +125C (industrial) |
| Package | 64-pin TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| ADC | 12-bit, up to 20 channels, 350 ksps |
| DAC | 10-bit, 350 ksps |
| Analog Comparators | 2 |
| SERCOM Modules | 6 (configurable UART/SPI/I2C) |
| USB | USB 2.0 Full-Speed Device/Host |
| DMA Channels | 12 |
| Event System Channels | 12 |
| Debug Interface | 2-pin Serial Wire Debug (SWD) |
| RoHS Status | Compliant |
ATSAMD21J16B-AF Pin Configuration
| Pin 1 | PA03 — GPIO/AIN[1]/VREFA |
| Pin 2 | PA04 — GPIO/AIN[2]/VREFB |
| Pin 3 | PA05 — GPIO/AIN[3] |
| Pin 4 | PA06 — GPIO/AIN[4] |
| Pin 5 | PA07 — GPIO/AIN[5] |
| Pin 6 | PA08 — GPIO/NMI |
| Pin 7 | PA09 — GPIO |
| Pin 8 | PA10 — GPIO |
| Pin 9 | PA11 — GPIO |
| Pin 10 | VDDIO — I/O supply |
| Pin 11 | GND — Ground |
| Pin 12 | PA12 — GPIO |
| Pin 13 | PA13 — GPIO |
| Pin 14 | PA14 — GPIO/XIN |
| Pin 15 | PA15 — GPIO/XOUT |
| Pin 16 | PA16 — GPIO |
| Pin 17 | PA17 — GPIO |
| Pin 18 | PA18 — GPIO |
| Pin 19 | PA19 — GPIO |
| Pin 20 | PA20 — GPIO |
| Pin 21 | PA21 — GPIO |
| Pin 22 | PA22 — GPIO |
| Pin 23 | PA23 — GPIO |
| Pin 24 | PA24 — GPIO/USB_DM |
| Pin 25 | PA25 — GPIO/USB_DP |
| Pin 26 | PA27 — GPIO |
| Pin 27 | PA28 — GPIO |
| Pin 28 | PA29 — GPIO |
| Pin 29 | PA30 — GPIO/SWCLK |
| Pin 30 | PA31 — GPIO/SWDIO |
| Pin 31 | PB00 — GPIO |
| Pin 32 | PB01 — GPIO |
| Pin 33 | PB02 — GPIO/AIN[10] |
| Pin 34 | PB03 — GPIO/AIN[11] |
| Pin 35 | PB04 — GPIO/AIN[12] |
| Pin 36 | PB05 — GPIO/AIN[13] |
| Pin 37 | PB06 — GPIO/AIN[14] |
| Pin 38 | PB07 — GPIO/AIN[15] |
| Pin 39 | PB08 — GPIO/AIN[16] |
| Pin 40 | PB09 — GPIO/AIN[17] |
| Pin 41 | PB10 — GPIO/AIN[18] |
| Pin 42 | PB11 — GPIO/AIN[19] |
| Pin 43 | PB12 — GPIO |
| Pin 44 | PB13 — GPIO |
| Pin 45 | PB14 — GPIO |
| Pin 46 | PB15 — GPIO |
| Pin 47 | PB16 — GPIO |
| Pin 48 | PB17 — GPIO |
| Pin 49 | PB18 — GPIO |
| Pin 50 | PB19 — GPIO |
| Pin 51 | PB20 — GPIO |
| Pin 52 | PB21 — GPIO |
| Pin 53 | PB22 — GPIO |
| Pin 54 | PB23 — GPIO |
| Pin 55 | PB24 — GPIO |
| Pin 56 | PB25 — GPIO |
| Pin 57 | PB26 — GPIO |
| Pin 58 | PB27 — GPIO |
| Pin 59 | PB28 — GPIO |
| Pin 60 | PB29 — GPIO |
| Pin 61 | PB30 — GPIO |
| Pin 62 | PB31 — GPIO |
| Pin 63 | VDDIO — I/O supply |
| Pin 64 | GND — Ground |
Typical Applications
ATSAMD21J16B-AF is suitable for 6 applications: IoT Sensor Nodes and Edge Devices, USB Human-Interface Devices, Capacitive Touch User Interfaces, Industrial Control and HMI Panels, Consumer Wearables and Fitness Devices, Battery Charging and Power Management Hosts.
IoT Sensor Nodes and Edge Devices
The ATSAMD21J16B-AF is an excellent fit for IoT sensor nodes thanks to its ARM Cortex-M0+ core at 48 MHz, 6 flexible SERCOM channels, and 12-bit ADC with up to 20 channels. Its idle current under 10 uA/MHz and sub-5 uA standby with RTC active let designs run for years on a coin cell. The 64KB Flash accommodates BLE or LoRaWAN stacks via a coprocessor over UART/SPI, and the Event System lets the ADC wake the MCU without CPU intervention. With the 12-channel DMA, sensor reads run autonomously, freeing the core for protocol logic and edge filtering.
Recommended
USB Human-Interface Devices
The ATSAMD21J16B-AF integrates USB 2.0 Full-Speed Device/Host with on-chip DFLL48M, eliminating the external 12 MHz crystal required by most USB microcontrollers. Its 48 MHz Cortex-M0+ core runs HID class drivers comfortably, and the 6 SERCOM channels let you expose keyboard, mouse, consumer-control, and vendor interfaces concurrently. The 64KB Flash fits USB stacks plus HID report logic, while 8KB SRAM handles double-buffered HID reports. On-chip 5V-tolerant GPIOs simplify direct connection to USB connectors without level shifters.
Recommended
Capacitive Touch User Interfaces
The ATSAMD21J16B-AF includes the Peripheral Touch Controller (PTC) supporting buttons, sliders, and wheels with up to 256 channels via the Y-lines. Combined with the 12-bit ADC for moisture compensation and the Event System for low-power wake-on-touch, the part delivers a robust touch UI in wearable, appliance, and industrial control panels. The 64KB Flash holds touch libraries and graphics rendering for small TFTs, while 8KB SRAM is sufficient for button debouncing and slider gesture state machines.
Recommended
Industrial Control and HMI Panels
With AEC-Q100 Grade 1 qualification and -40C to +125C operation, the ATSAMD21J16B-AF suits industrial HMI panels, sensor transmitters, and small PLCs. Its 6 SERCOM channels drive RS-485, RS-232, SPI displays, and I2C sensors simultaneously, while the 12-channel DMA offloads repetitive communication tasks. The 12-bit ADC with 20 channels reads multiple analog sensors, and the 10-bit DAC outputs analog control signals. Hardware crypto acceleration through the on-chip AES peripheral secures field-bus traffic.
Recommended
Consumer Wearables and Fitness Devices
The ATSAMD21J16B-AF powers wristband fitness trackers, heart-rate monitors, and BLE beacons thanks to its low active current, deep sleep modes, and integrated touch and ADC peripherals. The Cortex-M0+ runs sensor-fusion and BLE command shells while consuming under 7 mA active. The 64KB Flash holds BLE stacks and firmware update bootloaders, and the Event System lets an accelerometer interrupt wake the MCU directly. The 8KB SRAM buffers sensor samples before BLE transmission, extending battery life.
Recommended
Battery Charging and Power Management Hosts
The ATSAMD21J16B-AF serves as the host controller in smart battery chargers, power banks, and energy-harvesting nodes. Its 12-bit ADC monitors cell voltage and current with hardware averaging, the 10-bit DAC drives constant-current references, and the 6 SERCOMs talk to I2C fuel gauges and SPI displays. Low-power sleep modes let the device idle while a load is absent, while RTC calendar tracks time-of-day charging profiles. The 64KB Flash fits state-machine firmware and battery-protocol stacks.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J16B-AF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J16B-AFT | ATSAMD21J15B-AUT | ATSAMD21G18A-AF | ATSAMD21G17A-AF | ATSAMD21E16B-AF | ATSAMD21G15B-AF |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-TQFP (10x10) | 64-TQFP (10x10) - same | 64-TQFP (10x10) - same | 48-TQFP | 48-TQFP | 32-TQFP | 48-TQFP |
| Core | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ |
| Max Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Memory | 64 KB | 64 KB | 32 KB | 256 KB | 128 KB | 64 KB | 32 KB |
| SRAM | 8 KB | 8 KB | 4 KB | 32 KB | 16 KB | 8 KB | 4 KB |
| SERCOM Channels | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C |
Key Differentiators
- Maximum analog channel count in SAM D21 family (vs ATSAMD21G18A-AF)
- Best balance of Flash density and pin count (vs ATSAMD21J15B-AUT)
- Drop-in silicon revision with corrected errata (vs ATSAMD21J16A-AF)
Design Notes
Decouple VDDCORE with a 1uF X7R ceramic plus a 100nF X7R placed within 2 mm of the pin. VDDIO requires its own 100nF plus a bulk 1uF. Place the bulk capacitor on the same side of the PCB as the MCU, with vias to a ground island directly under the exposed pad. For USB-powered designs, add a 4.7uF bulk on VBUS to ride out inrush events. The on-chip voltage regulator needs no external inductor.
Route the 32.768 kHz crystal traces symmetrically and within 5 mm of the XIN/XOUT pins. Keep high-frequency digital traces (USB DP/DM, SWD) at least 3 mm away from the crystal. The USB differential pair must be 90 ohm impedance-controlled with no stubs, and the SWD pins should be brought to a 10-pin Cortex Debug header for production programming. The exposed thermal pad is not present on TQFP-64 but is on QFN variants - check the specific package.
Do not leave the RESET line floating - pull it up to VDDIO through a 10 kohm resistor with a 1 nF to 100 nF capacitor for noise rejection. Configure the NMI pin at startup so it is not driven by an external source inadvertently. When using the on-chip DFLL48M for USB, calibrate against the internal 48 MHz oscillator after each cold-boot. Last: confirm BOOTPROT fuse settings before locking the part, or you may brick production units.
Compliance Information
RoHS and REACH compliant per Microchip product page. AEC-Q100 Grade 1 qualified for automotive applications. Lead-free and halogen-free per Microchip environmental certification.
